The present invention is directed to a process and a device for manufacturing a composite consumable product by double extrusion.
EP 0,626,138 (Quaker Oats) discloses a process for manufacturing instant cereals, wherein a mixture based on cereal flour and water is cooked-extruded. The cooked-extruded mixture, to which pieces of food substance have been added, is shaped into flakes, the flakes toasted, coated with a sugar syrup to form a film on the surface thereof, and then dried.
U.S. Pat. No. 3,764,715 (Quaker Oats) discloses a process for manufacturing a coated instant cereal, wherein a mixture based on cereal flour and water is prepared, the mixture is cooked-extruded-expanded in the form of a tubular strand using an extruder equipped with a coextrusion die comprising an annular outlet orifice surrounding a central outlet orifice. A syrup is injected inside the tubular strand via the central outlet orifice. The cereal strand comprising the sugar syrup is cut into pieces at the die face, and the pieces are then dried so that the syrup which is present in the pieces diffuses from the inside towards the outside to form a film of dry syrup around the pieces.
EP 0,815,729 (Socixc3xa9txc3xa9 des Produits Nestlxc3xa9 S.A.) discloses a process for manufacturing a foodstuff by extrusion, wherein a first food substance to be processed is introduced into a first section of a twin-screw extruder, a second food substance to be processed is introduced into a second section of the twin-screw extruder separated dynamically from the first twin screw extruder, each food substance is processed independently in their section of the extruder and the two masses of food substance are extruded by being passed through at least one die and the extruded or coextruded products are cut up.
There remains a need, however, for a process and device for manufacturing composite consumable products that is simple and can be well controlled. The present invention provides such a device and process.
The invention is directed to a process for preparing a composite consumable food product by double extrusion. The process involves the steps of introducing one or more first foodstuffs into a first section of a twin screw extruder and processing the first foodstuffs in the first section to provide a liquid or pasty consumable substance; introducing one or more second foodstuffs into the second section of the twin-screw extruder and processing the second foodstuffs to provide a plasticized consumable substance, wherein the first and second sections off the twin screw extruder are separated by a dynamic separation device so that the first foodstuffs and the second foodstuffs can be processed separately; extruding the plasticized consumable substance to provide a strand of plasticized consumable substance; cutting the strand of plasticized consumable substance into pieces; and adding the liquid or pasty consumable substance to the plasticized consumable substance to provide the composite consumable food product.
The liquid or pasty consumable substance can be added to the plasticized consumable substance by coating the liquid or pasty consumable substance on the pieces of plasticized consumable substance. In one embodiment the liquid or pasty consumable substance can be coated on the plasticized consumable substance by coextruding the pasty or liquid consumable substance and the plasticized consumable substance through a die comprising a central orifice and a annular orifice wherein the plasticized consumable substance is extruded through the central orifice and the pasty or liquid consumable substance is extruded through the annular orifice so that the pasty or liquid consumable substance surrounds the strand of plasticized consumable substance. In another embodiment the liquid or pasty consumable substance is coated on the plasticized consumable substance after the strand of plasticized consumable substance has been cut by spraying the liquid or pasty consumable substance on the cut pieces of plasticized consumable substance while they are being mixed.
In another embodiment the liquid or pasty consumable substance can also be added to the plasticized consumable substance by coextruding the pasty or liquid consumable substance and the plasticized consumable substance through a die comprising a central orifice and a annular orifice wherein the pasty or liquid consumable substance is extruded through the central orifice and the plasticized consumable substance is extruded through the annular orifice so that the plasticized consumable substance surrounds the pasty or liquid consumable substance.
In yet another embodiment the liquid or pasty consumable substance is added to the plasticized consumable substance by injecting the liquid or pasty consumable substance into the plasticized consumable substance while the plasticized consumable substance is in the second section of the twin-screw extruder.
The process may further include the step of drying the composite consumable food product. The composite consumable food product may be dried to a moisture content of less than about 15 percent.
The second foodstuff may be wheat, barley, maize, rice flour, semolina, or mixtures thereof and water. The second foodstuff may further include one or more additional additives selected from the group consisting starch, sugar, fat or oil, a source of plant fiber, non-fatty milk solids from milk, vitamins, antioxidants, trace elements, flavorings, colorings, and mixtures thereof. The starch may be wheat, barley, rice, tapioca, potato, maize, or mixtures thereof. The sugar may be sucrose, fructose, glucose, or mixtures thereof.
The second foodstuff can have a water content of about 14 to 23 percent to provide a plasticized consumable substance that is expanded. The second foodstuff can also have a water content of about 24 to 36 percent to provide a plasticized consumable substance that is substantially non-expanded. The non-expanded plasticized consumable substance can be rolled and toasted to provide flakes.
The first foodstuff may be sugar, honey, water, or mixtures thereof and may further include milk powder, fruit or vegetable pulp or concentrate, cocoa powder, colorings, flavors, vitamins, trace elements, salt, spices, oils, materials or microorganisms with probiotic or prebiotic properties; functional plant extracts, or mixtures thereof. The sugar may be sucrose, fructose, dextrose, raw cane sugar, or mixtures thereof.
The first foodstuff may also be a protein hydrolysate and fat and may further include colorings, flavorings, vitamins, trace elements, and mixtures thereof.